Editing Alexander von Humboldt (section)

==Spanish American expedition, 1799–1804==
[[File:Map Alexander von Humboldt expedition-en.svg|thumb|upright=1.3|Alexander von Humboldt's Latin American expedition]]

===Seeking a foreign expedition===
With the financial resources to fund his scientific travels, he sought a ship on a major expedition. In the meantime, he went to Paris, where his brother Wilhelm was living. Paris was a great center of scientific learning and his brother and sister-in-law Caroline were well connected in those circles. [[Louis-Antoine de Bougainville]] urged Humboldt to accompany him on a major expedition, likely to last five years, but the French revolutionary [[Directoire]] placed [[Nicolas Baudin]] at the head of it rather than the aging scientific traveler.{{sfn|de Terra|1955|p=80}} On the postponement of Captain Baudin's proposed voyage of [[circumnavigation]] due to continuing warfare in Europe, which Humboldt had been officially invited to accompany, Humboldt was deeply disappointed. He had already selected scientific instruments for his voyage. He did, however, have a stroke of luck with meeting [[Aimé Bonpland]], the botanist and physician for the voyage.

Discouraged, the two left Paris for [[Marseille]], where they hoped to join [[Napoleon I of France|Napoleon Bonaparte]] in Egypt, but North Africans were in revolt against the French invasion in Egypt and French authorities refused permission to travel. Humboldt and Bonpland eventually found their way to [[Madrid]], where their luck changed spectacularly.{{sfn|de Terra|1955|p=83}}

===Spanish royal authorization, 1799===
[[File:Carlos IV de rojo.jpg|thumb|upright|[[Charles IV of Spain]] who authorized Humboldt's travels and research in Spanish America]]
In Madrid, Humboldt sought authorization to travel to Spain's realms in the Americas; he was aided in obtaining it by the German representative of Saxony at the royal Bourbon court. Baron Forell had an interest in mineralogy and science endeavors and was inclined to help Humboldt.{{sfn|de Terra|1955|p=83}} At that time, the [[Bourbon Reforms]] sought to reform administration of the realms and revitalize their economies.<ref>[[Ida Altman]], Sarah Cline, Javier Pescador, ''The Early History of Greater Mexico''. Prentice Hall, 2003, pp. 300–317.</ref> At the same time, the [[Spanish Enlightenment]] was in florescence. For Humboldt "the confluent effect of the Bourbon revolution in government and the Spanish Enlightenment had created ideal conditions for his venture".{{sfn|Brading|1991|p=517}}

The Bourbon monarchy had already authorized and funded expeditions, with the [[Botanical Expedition to the Viceroyalty of Peru]] to Chile and Peru (1777–88), New Granada (1783–1816), New Spain (Mexico) (1787–1803), and the [[Malaspina Expedition]] (1789–94). These were lengthy, state-sponsored enterprises to gather information about plants and animals from the Spanish realms, assess economic possibilities, and provide plants and seeds for the Royal Botanical Garden in Madrid (founded 1755).{{sfn|Bleichmar|2012|p=5}} These expeditions took naturalists and artists, who created visual images as well as careful written observations as well as collecting seeds and plants themselves.{{sfn|Bleichmar|2012|p=19}} Crown officials as early as 1779 issued and systematically distributed ''Instructions concerning the most secure and economic means to transport live plants by land and sea from the most distant countries'', with illustrations, including one for the crates to transport seeds and plants.<ref>Casimiro Gómez Ortega, ''Instrucción sobre el modo más seguro y económico de transportar plantas vivas por mar y tierra a los países más distantes ilustrada con láminas. Añadese el método de desacar las plants para formar herbarios'' (Madrid 1779). Biblioteca del Real Jardín Botánico, Madrid, cited in {{harvnb|Bleichmar|2012|pp=26–27}}.</ref>

When Humboldt requested authorization from the crown to travel to Spanish America, most importantly, with his own financing, it was given positive response. Spain under the Habsburg monarchy had guarded its realms against foreigner travelers and intruders. The Bourbon monarch was open to Humboldt's proposal. Spanish Foreign Minister Don [[Mariano Luis de Urquijo]] received the formal proposal and Humboldt was presented to the monarch in March 1799.{{sfn|de Terra|1955|p=83}} Humboldt was granted access to crown officials and written documentation on Spain's empire. With Humboldt's experience working for the absolutist Prussian monarchy as a government mining official, Humboldt had both the academic training and experience of working well within a bureaucratic structure.{{sfn|Brading|1991|p=517}}
[[File:Alexandre humboldt.jpg|thumb|upright|Portrait of Alexander von Humboldt by [[Friedrich Georg Weitsch]], 1806]]

Before leaving Madrid in 1799, Humboldt and Bonpland visited the [[Museo Nacional de Ciencias Naturales|Natural History Museum]], which held results of [[Martín Sessé y Lacasta]] and [[José Mariano Mociño]]'s botanical expedition to [[New Spain]].<ref>Stephen T. Jackson, "Biographical Sketches" in ''Essay on the Geography of Plants'' by Alexander von Humboldt and Aimé Bonpland. Edited by Stephen T. Jackson, translated by Sylvie Romanowski. Chicago: University of Chicago Press 2009, p. 248.</ref> Humboldt and Bonpland met [[Hipólito Ruiz López]] and [[José Antonio Pavón y Jiménez]] of the royal expedition to Peru and Chile in person in Madrid and examined their botanical collections.<ref>Jackson, "Biographical Sketches" pp. 245, 246–247.</ref>

===Venezuela, 1799–1800===
[[File:Humboldt and Bonplant in the Jungle.jpg|thumb|Humboldt and [[Aimé Bonpland]] were in the Amazon rainforest by the [[Casiquiare River]], with their scientific instruments, which enabled them to take many types of accurate measurements throughout their five-year journey. Oil painting by [[Eduard Ender]], 1856. Humboldt did not like the painting as the instruments depicted were inaccurate.<ref>Andrea Wulf (2015). The invention of nature, the adventures of Alexander von Humboldt, the lost hero of science</ref>]]
[[Image:Canal do Cassiquiare.jpg|thumb|upright=1.2|Map of the Cassiquiare canal based on Humboldt's 1799 observations]]
Armed with authorization from the King of Spain, Humboldt and Bonpland made haste to sail, taking the ship ''Pizarro'' from [[A Coruña]], on 5 June 1799. The ship stopped six days on the island of [[Tenerife]], where Humboldt climbed the volcano [[Teide]], and then sailed on to the New World, landing at [[Cumaná]], [[Venezuela]], on 16 July.

The ship's destination was not originally Cumaná, but an outbreak of typhoid on board meant that the captain changed course from [[Havana]] to land in northern South America. Humboldt had not mapped out a specific plan of exploration, so that the change did not upend a fixed itinerary. He later wrote that the diversion to Venezuela made possible his explorations along the Orinoco River to the border of Portuguese Brazil. With the diversion, the ''Pizarro'' encountered two large dugout canoes each carrying 18 Guayaqui Indians. The ''Pizarro''{{'}}s captain accepted the offer of one of them to serve as pilot. Humboldt hired this Indian, named Carlos del Pino, as a guide.{{sfn|de Terra|1955|pp=91–92}}

Venezuela from the 16th to the 18th centuries was a relative backwater compared to the seats of the Spanish viceroyalties based in New Spain (Mexico) and Peru, but during the Bourbon reforms, the northern portion of Spanish South America was reorganized administratively, with the 1777 establishment of a captaincy-general based at Caracas. A great deal of information on the new jurisdiction had already been compiled by François de Pons, but was not published until 1806.{{sfn|Brading|1991|p=517}}<ref>F.J. de Pons. ''Voyage à la partie orientale de la Terre-Ferme, dans l'Amérique Méridionale, fait pendant les années 1801, 1802, 1803 et 1804 : contenant la description de la capitainerie générale de Carácas, composée des provinces de Vénézuéla, Maracaïbo, Varinas, la Guiane Espagnole, Cumana, et de l'île de la Marguerite ....'' Paris: Colnet 1806. It was also published in English the same year.</ref>

Rather than describe the administrative center of Caracas, Humboldt started his researches with the valley of Aragua, where export crops of sugar, coffee, cacao, and cotton were cultivated. Cacao plantations were the most profitable, as world demand for chocolate rose.{{sfn|Brading|1991|p=518}} It is here that Humboldt is said to have developed his idea of human-induced climate change. Investigating evidence of a rapid fall in the water level of the valley's Lake Valencia, Humboldt credited the desiccation to the clearance of tree cover and to the inability of the exposed soils to retain water. With their clear cutting of trees, the agriculturalists were removing the woodland's "threefold" moderating influence upon temperature: cooling shade, evaporation and radiation.{{sfn|Wulf|2015|pages=56–59}}

Humboldt visited the mission at [[Caripe]] and explored the [[Cueva del Guácharo National Park|Guácharo cavern]], where he found the [[oilbird]], which he was to make known to science as ''Steatornis caripensis''. He also described the [[Lake Bermudez|Guanoco]] asphalt lake as "The spring of the good priest" ("''Quelle des guten Priesters''").<ref>{{cite web|url=http://www.inveas.org.ve/noticias.asp?id=20 |title=Instituto Venezolano del Asfalto |access-date=2010-08-28 |url-status=dead |archive-url=https://web.archive.org/web/20120310235811/http://www.inveas.org.ve/noticias.asp?id=20 |archive-date=2012-03-10 }}, Instituto Venezolano del Asfalto INVEAS.org</ref><ref>{{cite web|url=http://www.parianatours.com/regionen/paria.html|title=Paría – ein abwechslungsreiches Stück Land|website=PariaTours.de|language=de|access-date=20 March 2021|archive-date=20 June 2020|archive-url=https://web.archive.org/web/20200620180938/http://www.parianatours.com/regionen/paria.html|url-status=live}}</ref> Returning to Cumaná, Humboldt observed, on the night of 11–12 November, a remarkable [[meteor shower]] (the [[Leonids]]). He proceeded with Bonpland to [[Caracas]] where he climbed the [[El Ávila National Park|Avila mount]] with the young poet [[Andrés Bello]], the former tutor of [[Simón Bolívar]], who later became the leader of independence in northern South America. Humboldt met the Venezuelan Bolívar himself in 1804 in Paris and spent time with him in Rome. The documentary record does not support the supposition that Humboldt inspired Bolívar to participate in the struggle for independence, but it does indicate Bolívar's admiration for Humboldt's production of new knowledge on Spanish America.{{sfn|de Terra|1955|pp=232–233}}

In February 1800, Humboldt and Bonpland left the coast with the purpose of exploring the course of the [[Orinoco River]] and its tributaries. This trip, which lasted four months and covered {{convert|1725|mi|km}} of wild and largely uninhabited country, had an aim of establishing the existence of the [[Casiquiare canal]] (a communication between the water systems of the rivers Orinoco and [[Amazon River|Amazon]]). Although, unbeknownst to Humboldt, this existence had been established decades before,{{sfn|Wulf|2015|p={{page needed|date=January 2021}}}} his expedition had the important results of determining the exact position of the [[River bifurcation|bifurcation]],<ref name="EB1911"/> and documenting the life of several native tribes such as the Maipures and their extinct rivals the Atures (several words of the latter tribe were transferred to Humboldt by one parrot<ref>Mark Forsyth. The etymologicon. Icon Books Ltd. London N79DP, (2011), p. 123.</ref>). Around 19 March 1800, Humboldt and Bonpland discovered dangerous [[electric eel]]s, whose shock could kill a man. To catch them, locals suggested they drive wild horses into the river, which brought the eels out from the river mud, and resulted in a violent confrontation of eels and horses, some of which died. Humboldt and Bonpland captured and dissected some eels, which retained their ability to shock; both received potentially dangerous electric shocks during their investigations. The encounter made Humboldt think more deeply about electricity and magnetism, typical of his ability to extrapolate from an observation to more general principles.<ref>{{harvnb|Wulf|2015|pp=62–63}}. Wulf's book includes a picture of the encounter (p. 63); she captions it "The battle between horses and electric eels".</ref> Humboldt returned to the incident in several of his later writings, including his travelogue ''Personal Narrative'' (1814–29), ''Views of Nature'' (1807), and ''Aspects of Nature'' (1849).<ref>Cited in {{harvnb|Wulf|2015|p=362}}, n. 62.</ref>

Two months later, they explored the territory of the Maipures and that of the then-recently extinct Atures Indians. Humboldt laid to rest the persistent myth of [[Walter Raleigh]]'s [[Lake Parime]] by proposing that the seasonal flooding of the [[Rupununi savannah]] had been misidentified as a lake.<ref>Humboldt, Alexander von. [https://web.archive.org/web/20080813083851/http://ebooks.adelaide.edu.au/h/humboldt/alexander/travels/chapter25.html ''Personal Narrative of Travels to the Equinoctial Regions of America During the Years 1799–1804'', Chapter 25. Henry G. Bohn, London, 1853.] </ref>

===Cuba, 1800, 1804===
[[File:Chiranthodendron_pentadactylon_monochrome.jpeg|thumb|Humboldt botanical drawing published in his work on Cuba]]
On 24 November 1800, the two friends set sail for Cuba, landing on 19 December,{{sfn|Nicolson|Wilson|1995|p=lxviii}} where they met fellow botanist and [[plant collector]] [[John Fraser (botanist)|John Fraser]].<ref>Brendel, Frederick, [https://www.jstor.org/stable/2449332 Historical Sketch of the Science of Botany in North America from 1635 to 1840] {{Webarchive|url=https://web.archive.org/web/20181215124932/https://www.jstor.org/stable/2449332 |date=2018-12-15 }}, ''The American Naturalist'', 13:12 (December 1879), pp. 754–771, ''The University of Chicago Press''; accessed 31 July 2012.</ref> Fraser and his son had been shipwrecked off the Cuban coast, and did not have a license to be in the Spanish Indies. Humboldt, who was already in Cuba, interceded with crown officials in Havana, as well as giving them money and clothing. Fraser obtained permission to remain in Cuba and explore. Humboldt entrusted Fraser with taking two cases of Humboldt and Bonpland's botanical specimens to England when he returned, for eventual conveyance to the German botanist Willdenow in Berlin.{{sfn|de Terra|1955|pp=116–117}} Humboldt and Bonpland stayed in Cuba until 5 March 1801, when they left for the mainland of northern South America again, arriving there on 30 March.

Humboldt is considered to be the "second discoverer of Cuba" due to the scientific and social research he conducted on this Spanish colony. During an initial three-month stay at [[Havana]], his first tasks were to survey that city properly and the nearby towns of [[Guanabacoa]], [[Regla]], and [[Bejucal]]. He befriended Cuban landowner and thinker [[Francisco de Arango y Parreño]]; together they visited the {{lang|es|Guines}} area in south Havana, the valleys of [[Matanzas]] Province, and the [[Valley of the Sugar Mills]] in [[Trinidad, Cuba|Trinidad]]. Those three areas were, at the time, the first frontier of sugar production in the island. During those trips, Humboldt collected statistical information on Cuba's population, production, technology and trade, and with Arango, made suggestions for enhancing them. He predicted that the agricultural and commercial potential of Cuba was huge and could be vastly improved with proper leadership in the future.

On their way back to Europe from the Americas, Humboldt and Bonpland stopped again in Cuba, leaving from the port of Veracruz and arriving in Cuba on 7 January 1804, staying until 29 April 1804. In Cuba, he collected plant material and made extensive notes. During this time, he socialized with his scientific and landowner friends, conducted mineralogical surveys, and finished his vast collection of the island's flora and fauna that he eventually published as ''Essai politique sur l'îsle de Cuba''.{{Sfn|Humboldt chronology|p= lxix}}

===The Andes, 1801–1803===
[[File:Humboldt-Bonpland Chimborazo.jpg|thumb|upright=1.2|Humboldt and his fellow scientist Aimé Bonpland near the foot of the [[Chimborazo]] volcano, painting by [[Friedrich Georg Weitsch]] (1810)]]

After their first stay in Cuba of three months, they returned to the mainland at [[Cartagena de Indias]] (now in Colombia), a major center of trade in northern South America. Ascending the swollen stream of the [[Magdalena River]] to Honda, they arrived in Bogotá on 6 July 1801, where they met the Spanish botanist [[José Celestino Mutis]], head of the Royal Botanical Expedition to New Granada, staying there until 8 September 1801. Mutis was generous with his time and gave Humboldt access to the huge pictorial record he had compiled since 1783. Mutis was based in Bogotá, but as with other Spanish expeditions, he had access to local knowledge and a workshop of artists, who created highly accurate and detailed images. This type of careful recording meant that even if specimens were not available to study at a distance, "because the images travelled, the botanists did not have to".{{sfn|Bleichmar|2012|p=190}} Humboldt was astounded at Mutis's accomplishment; when Humboldt published his first volume on botany, he dedicated it to Mutis "as a simple mark of our admiration and acknowledgement".<ref>Alexander von Humboldt and Aimé Bonpland, ''Plantes équinoxiles, in ''Voyage de Humboldt et Bonpland, Sixième Partie, Botanique, vo. 1 Paris 1808.</ref>

Humboldt had hopes of connecting with the French sailing expedition of Baudin, now finally underway, so Bonpland and Humboldt hurried to Ecuador.{{Sfn|Humboldt chronology|p= lxix}} They crossed the frozen ridges of the [[Cordillera Real (Ecuador)|Cordillera Real]] and reached [[Quito]] on 6 January 1802, after a tedious and difficult journey.

Their stay in Ecuador was marked by the ascent of [[Pichincha (volcano)|Pichincha]] and their climb of [[Chimborazo]], where Humboldt and his party reached an altitude of {{convert|19286|ft|m}}. This was a world record at the time (for a westerner—[[Inca Empire|Incas]] had reached much higher altitudes centuries before),<ref>{{cite journal|last1=Mignone|first1=Pablo|title=Ritualidad estatal, capacocha y actores sociales locales: El Cementerio del volcán Llullaillaco|journal=[[Estudios Atacameños]]|date=2010|issue=40|pages=43–62|doi=10.4067/S0718-10432010000200004|language=es|issn=0718-1043|doi-access=free|quote=[D]iscutimos el clásico enfoque arqueológico acerca de este tipo de ritual como dominio exclusivo y protagónico del Estado inca [...] Luego el camino se bifurca para dirigirse uno hacia una plataforma de entierro, a 6715 m.snm, y el otro a la cima del volcán, unos 20 m más arriba.|hdl=11336/14124|hdl-access=free}}</ref> but 1000 feet short of the summit.<ref>Humboldt's claim was disputed by mountaineer [[Edward Whymper]] when he made the first ascent of Chimborazo in 1880.{{cite book|last=Whymper|first=Edward|author-link=Edward Whymper|title=Travels amongst the Great Andes of the Equator |url=https://archive.org/details/amongstgr00whymtravelsrich |publisher=John Murray |year=1892 |pages=[https://archive.org/details/amongstgr00whymtravelsrich/page/30 30]–32}}</ref> Humboldt's journey concluded with an expedition to the sources of the Amazon ''en route'' for [[Lima]], Peru.<ref>{{cite journal | last1 = Muratta Bunsen | first1 = Eduardo | year = 2010 | title = El conflicto entre eurocentrismo y empatía en la literatura de viajes de Humboldt | journal = Revista Andina | volume = 50 | pages = 247–262 }}</ref>

At [[Callao]], the main port for Peru, Humboldt observed the [[transit of Mercury]] on 9 November and studied the fertilizing properties of [[guano]], rich in nitrogen, the subsequent introduction of which into Europe was due mainly to his writings.<ref name="EB1911"/>

===New Spain (Mexico), 1803–1804===
[[File:MINA_GTO.jpg|thumb|Silver mining complex of La Valenciana, Guanajuato, Mexico]]
[[File:Vues des Cordillères, et monumens des peuples indigènes de l'Amérique (1813) (14781309784).jpg|thumb|upright|[[Basaltic Prisms of Santa María Regla|Basalt prisms at Santa María Regla]], Mexico by Alexander von Humboldt, published in ''Vue des Cordillères et monuments des peuples indigènes de l'Amérique'']]
[[File:1479 Stein der fünften Sonne, sog. Aztekenkalender, Ollin Tonatiuh anagoria.JPG|thumb|Aztec calendar stone]]
[[File:Humboldt 1810 pp 47 48 50 51 52.jpg|thumb|[[Dresden Codex]], later identified as a Maya manuscript, published in part by Humboldt in 1810]]
Humboldt and Bonpland had not intended to go to New Spain, but when they were unable to join a voyage to the Pacific, they left the Ecuadorian port of Guayaquil and headed for [[Acapulco]] on Mexico's west coast. Even before Humboldt and Bonpland started on their way to New Spain's [[Mexico City|capital]] on Mexico's central plateau, Humboldt realized the captain of the vessel that brought them to Acapulco had reckoned its location incorrectly. Since Acapulco was the main west-coast port and the terminus of the [[Manila Galleon|Asian trade]] from the Spanish Philippines, having accurate maps of its location was extremely important. Humboldt set up his instruments, surveying the deep-water bay of Acapulco, to determine its longitude.{{sfn|de Terra|1955|pp=149–150}}{{Sfn|Humboldt chronology|p= lxviii–lxvix}}

Humboldt and Bonpland landed in Acapulco on 15 February 1803, and from there they went to [[Taxco]], a silver-mining town in modern [[Guerrero]]. In April 1803, he visited [[Cuernavaca]], [[Morelos]]. Impressed by its climate, he nicknamed the city the ''City of Eternal Spring''.<ref>{{cite web|url=https://masdemorelos.masdemx.com/2018/04/cuernavaca-morelos-eterna-primavera-von-humboldt-exploraciones-historia/|title=La breve exploración de este magnífico personaje puso a Cuernavaca en el mapa mundial|language=es|website=masdemorelos.masdemx.com|date=3 April 2018|access-date=21 April 2021|archive-date=10 April 2019|archive-url=https://web.archive.org/web/20190410214717/https://masdemorelos.masdemx.com/2018/04/cuernavaca-morelos-eterna-primavera-von-humboldt-exploraciones-historia/|url-status=live}}</ref><ref>http://www.moreloshabla.com/morelos/cuernavaca/por-que-le-decimos-ciudad-de-la-eterna-primavera-a-cuernavaca/ {{Webarchive|url=https://web.archive.org/web/20181218191121/http://www.moreloshabla.com/morelos/cuernavaca/por-que-le-decimos-ciudad-de-la-eterna-primavera-a-cuernavaca/ |date=2018-12-18 }} accessed Dec 28, 2018</ref> Humboldt and Bonpland arrived in Mexico City, having been officially welcomed via a letter from the king's representative in New Spain, Viceroy Don [[José de Iturrigaray]]. Humboldt was also given a special passport to travel throughout New Spain and letters of introduction to intendants, the highest officials in New Spain's administrative districts (intendancies). This official aid to Humboldt allowed him to have access to crown records, mines, landed estates, canals, and Mexican antiquities from the prehispanic era.{{sfn|de Terra|1955|p=156}} Humboldt read the writings of Bishop-elect of the important diocese of Michoacan [[Manuel Abad y Queipo]], a [[classical liberal]], that were directed to the crown for the improvement of New Spain.{{sfn|Brading|1991|p=527}}

They spent the year in the viceroyalty, traveling to different Mexican cities in the central plateau and the northern mining region. The first journey was from Acapulco to Mexico City, through what is now the Mexican state of [[Guerrero]]. The route was suitable only for mule train, and all along the way, Humboldt took measurements of elevation. When he left Mexico a year later in 1804, from the east coast port of Veracruz, he took a similar set of measures, which resulted in a chart in the ''Political Essay'', the physical plan of Mexico with the dangers of the road from Acapulco to Mexico City, and from Mexico City to Veracruz.<ref>''Plano físico de la Nueva España, Perfil del Camino de Acapulco a Mégico [sic], y de Mégico a Veracruz''. Chart is published in Magali M. Carrera, ''Traveling from New Spain to Mexico: Mapping Practices of Nineteenth-century Mexico'', Durham: Duke University Press 2011, p. 70, plate 18.</ref> This visual depiction of elevation was part of Humboldt's general insistence that the data he collected be presented in a way more easily understood than statistical charts. A great deal of his success in gaining a more general readership for his works was his understanding that "anything that has to do with extent or quantity can be represented geometrically. Statistical projections [charts and graphs], which speak to the senses without tiring the intellect have the advantage of bringing attention to a large number of important facts".<ref>Alexander von Humboldt, ''Atlás géographique et physique du Royaume de la Nouvelle-Espagne'', lxxxiii–lxxiv, quoted in Anne Godlewska, ''Geography Unbound: French Geographic Science from Cassini to Humboldt''. Chicago: University of Chicago Press 1999, p. 257.</ref>

Humboldt was impressed with Mexico City, which at the time was the largest city in the Americas, and one that could be counted as modern. He declared "no city of the new continent, without even excepting those of the United States, can display such great and solid scientific establishments as the capital of Mexico".<ref>Humboldt, ''Political essay'', p. 74.</ref> He pointed to the [[Palacio de Minería#History|Royal College of Mines]], the [[National Palace (Mexico)#Viceregal palace|Royal Botanical Garden]] and the [[Academy of San Carlos|Royal Academy of San Carlos]] as exemplars of a metropolitan capital in touch with the latest developments on the continent and insisting on its modernity.{{sfn|Brading|1991|pp=526–527}} He also recognized important [[Criollo people|criollo]] savants in Mexico, including [[José Antonio de Alzate y Ramírez]], who died in 1799, just before Humboldt's visit; Miguel Velásquez de León; and [[Antonio de León y Gama]].{{sfn|Brading|1991|p=527}}

Humboldt spent time at the Valenciana silver mine in [[Guanajuato]], central New Spain, at the time the most important in the Spanish empire.{{sfn|Brading|1991|p=525}} The bicentennial of his visit in Guanajuato was celebrated with a conference at the [[University of Guanajuato]], with Mexican academics highlighting various aspects of his impact on the city.<ref>José Luis Lara Valdés, ''Bicentenario de Humboldt en Guanajuato (1803–2003)''. Guanajuato: Ediciones La Rana 2003.</ref> Humboldt could have simply examined the geology of the fabulously rich mine, but he took the opportunity to study the entire mining complex as well as analyze mining statistics of its output. His report on silver mining is a major contribution, and considered the strongest and best informed section of his ''Political Essay''. Although Humboldt was himself a trained geologist and mining inspector, he drew on mining experts in Mexico. One was [[Fausto Elhuyar]], then head of the General Mining Court in Mexico City, who, like Humboldt was trained in Freiberg. Another was [[Andrés Manuel del Río]], director of Royal College of Mines, whom Humboldt knew when they were both students in Freiberg.{{sfn|de Terra|1955|pp=51, 156}} The Bourbon monarchs had established the mining court and the college to elevate mining as a profession, since revenues from silver constituted the crown's largest source of income. Humboldt also consulted other German mining experts, who were already in Mexico.{{sfn|Brading|1991|p=527}} While Humboldt was a welcome foreign scientist and mining expert, the Spanish crown had established fertile ground for Humboldt's investigations into mining.

Spanish America's ancient civilizations were a source of interest for Humboldt, who included images of Mexican manuscripts (or codices) and Inca ruins in his richly illustrated ''Vues des cordillères et monuments des peuples indigènes de l'Amerique'' (1810–1813), the most experimental of Humboldt's publications, since it does not have "a single ordering principle" but his opinions and contentions based on observation.{{sfn|Kutzinski|Ette|2012|page=xxi}} For Humboldt, a key question was the influence of climate on the development of these civilizations.{{sfn|Brading|1991|p=523}} When he published his ''Vues des cordillères'', he included a color image of the [[Aztec calendar stone]], which had been discovered buried in the [[Zócalo|main plaza]] of Mexico City in 1790, along with select drawings of the [[Dresden Codex]] and others he sought out later in European collections. His aim was to muster evidence that these pictorial and sculptural images could allow the reconstruction of prehispanic history. He sought out Mexican experts in the interpretation of sources from there, especially Antonio Pichardo, who was the literary executor of [[Antonio de León y Gama]]'s work. For American-born Spaniards ([[Criollo people|criollos]]) who were seeking sources of pride in Mexico's ancient past, Humboldt's recognition of these ancient works and dissemination in his publications was a boon. He read the work of exiled Jesuit [[Francisco Javier Clavijero]], which celebrated Mexico's prehispanic civilization, and which Humboldt invoked to counter the pejorative assertions about the new world by Buffon, de Pauw, and Raynal.{{sfn|Kutzinski|Ette|2012|p=xv}} Humboldt ultimately viewed both the prehispanic realms of Mexico and Peru as despotic and barbaric.{{sfn|Brading|1991|pp=523–525}} However, he also drew attention to indigenous monuments and artifacts as cultural productions that had "both ... historical ''and'' artistic significance".{{sfn|Kutzinski|Ette|2012|p=xxxiii}}

One of his most widely read publications resulting from his travels and investigations in Spanish America was the ''Essai politique sur le royaum de la Nouvelle Espagne'', quickly translated to English as ''Political Essay on the Kingdom of New Spain'' (1811).<ref>''Political Essay on the Kingdom of New Spain'', (four volumes) translator John Black, London/Edinburgh: Longman, Hurst, Rees Orme and brown; and H. Colborn and W. Blackwood, and Brown and Crombie, Edinburgh 1811.</ref> This treatise was the result of Humboldt's own investigations as well as the generosity of Spanish colonial officials for statistical data.<ref>Benjamin Keen, "Alexander von Humboldt" in ''Encyclopedia of Mexico''. Chicago: Fitzroy Dearborn 1997, p. 664.</ref>

===The United States, 1804===
[[File:Louisiana1804a.jpg|thumb|1804 map of the Louisiana Territory. Jefferson and his cabinet sought information from Humboldt when he visited Washington, D.C., about Spain's territory in Mexico, now bordering the U.S.]]

Leaving from Cuba, Humboldt decided to take an unplanned short visit to the United States. Knowing that the current U.S. president, [[Thomas Jefferson]], was himself a scientist, Humboldt wrote to him saying that he would be in the United States. Jefferson warmly replied, inviting him to visit the [[White House]] in the nation's new capital. In his letter Humboldt had gained Jefferson's interest by mentioning that he had discovered [[mammoth]] teeth near the Equator. Jefferson had previously written that he believed mammoths had never lived so far south. Humboldt had also hinted at his knowledge of New Spain.<ref name="Schwarz-2001">{{cite journal |last=Schwarz |first=Ingo |date=2001-01-01 |title=Alexander von Humboldt's Visit to Washington and Philadelphia, His Friendship with Jefferson, and His Fascination with the United States |journal=Northeastern Naturalist |volume=8 |pages=43–56|doi=10.1656/1092-6194(2001)8[43:AVHVTW]2.0.CO;2 }}</ref>

Arriving in [[Philadelphia]], which was a center of learning in the U.S., Humboldt met with some of the major scientific figures of the era, including chemist and anatomist [[Caspar Wistar (physician)|Caspar Wistar]], who pushed for compulsory smallpox vaccination, and botanist [[Benjamin Smith Barton]], as well as physician [[Benjamin Rush]], a signer of the [[United States Declaration of Independence|Declaration of Independence]], who wished to hear about [[cinchona]] bark from a South American tree, which cured fevers.{{sfn|de Terra|1955|pp=175–176}} Humboldt's treatise on cinchona was published in English in 1821.<ref>{{cite book |first=Alexander von |last=Humboldt |url=https://www.biodiversitylibrary.org/item/14437 |title=An illustration of the genus Cinchona | publisher=Printed for J. Searle | location=London | year=1821 | doi=10.5962/bhl.title.715}}</ref>

After arriving in Washington D.C, Humboldt held numerous intense discussions with Jefferson on both scientific matters and also his year-long stay in New Spain. Jefferson had only recently concluded the [[Louisiana Purchase]], which now placed New Spain on the southwest border of the United States. The Spanish minister in Washington, D.C. had declined to furnish the U.S. government with information about Spanish territories, and access to the territories was strictly controlled. Humboldt was able to supply Jefferson with the latest information on the population, trade agriculture and military of New Spain. This information would later be the basis for his ''Essay on the Political Kingdom of New Spain'' (1810).

Jefferson was unsure of where the border of the newly-purchased [[Louisiana]] was precisely, and Humboldt wrote him a two-page report on the matter. Jefferson would later refer to Humboldt as "the most scientific man of the age". [[Albert Gallatin]], Secretary of the Treasury, said of Humboldt "I was delighted and swallowed more information of various kinds in less than two hours than I had for two years past in all I had read or heard." Gallatin, in turn, supplied Humboldt with information he sought on the United States.<ref name="Schwarz-2001"/>

After six weeks, Humboldt set sail for Europe from the mouth of the [[Delaware River|Delaware]] and landed at [[Bordeaux]] on 3 August 1804.

===Travel diaries===
Humboldt kept a detailed diary of his sojourn to Spanish America, running some 4,000 pages, which he drew on directly for his multiple publications following the expedition. The leather-bound diaries themselves are now in Germany, having been returned from Russia to East Germany, where they were taken by the Red Army after World War II. Following German reunification, the diaries were returned to a descendant of Humboldt. For a time, there was concern about their being sold, but that was averted.<ref>[https://www.dw.com/en/humboldt-america-diaries-to-stay-in-germany/a-17271671 "Humboldt 'America' diaries to stay in Germany"] {{Webarchive|url=https://web.archive.org/web/20200610003917/https://www.dw.com/en/humboldt-america-diaries-to-stay-in-germany/a-17271671 |date=2020-06-10 }}, [[Deutsche Welle]], 4 December 2013. Accessed 6 April 2021</ref> A government-funded project to digitize the Spanish American expedition as well as his later Russian expedition has been undertaken (2014–2017) by the University of Potsdam and the German State Library–Prussian Cultural Heritage Foundation.<ref>http://www.uni-potsdam.de/tapoints/?p=1654 {{Webarchive|url=https://web.archive.org/web/20170302030831/http://www.uni-potsdam.de/tapoints/?p=1654 |date=2017-03-02 }} accessed 1 March 2017.</ref>

===Achievements of the Hispanic American expedition===
{{see also|Humboldtian science}}
Humboldt's decades' long endeavor to publish the results of this expedition not only resulted in multiple volumes, but also made his international reputation in scientific circles. Humboldt came to be well-known with the reading public as well, with popular, densely illustrated, condensed versions of his work in multiple languages. Bonpland, his fellow scientist and collaborator on the expedition, collected botanical specimens and preserved them, but unlike Humboldt who had a passion to publish, Bonpland had to be prodded to do the formal descriptions. Many scientific travelers and explorers produced huge visual records, which remained unseen by the general public until the late nineteenth century, in the case of the Malaspina Expedition, and even the late twentieth century, when Mutis's botanical, some 12,000 drawings from New Granada, was published. Humboldt, by contrast, published immediately and continuously, using and ultimately exhausting his personal fortune, to produce both scientific and popular texts. Humboldt's name and fame were made by his travels to Spanish America, particularly his publication of the ''Political Essay on the Kingdom of New Spain''. His image as the premier European scientist was a later development.<ref>Nicolaas Rupke, "A Geography of Enlightenment: The Critical Reception of Alexander von Humboldt's Mexico Work". In ''Geography and Enlightenment'', edited by David N. Livingstone and Charles W. J. Withers, 319–339. Chicago: University of Chicago Press 1999.</ref>

For the Bourbon crown, which had authorized the expedition, the returns were not only tremendous in terms of sheer volume of data on their New World realms, but in dispelling the vague and pejorative assessments of the New World by [[Guillaume-Thomas Raynal]], [[Georges-Louis Leclerc, Comte de Buffon]], and [[William Robertson (historian)|William Robertson]]. The achievements of the Bourbon regime, especially in New Spain, were evident in the precise data Humboldt systematized and published.{{sfn|Brading|1991|p=527}}

This memorable expedition may be regarded as having laid the foundation of the sciences of [[physical geography]], [[plant geography]], and [[meteorology]]. Key to that was Humboldt's meticulous and systematic measurement of phenomena with the most advanced instruments then available. He closely observed plant and animal species in situ, not just in isolation, noting all elements in relation to one other. He collected specimens of plants and animals, dividing the growing collection so that if a portion was lost, other parts might survive.

[[File:Frederich heinrich baron von humboldt-charles wilson peale.JPG|thumb|upright|Humboldt depicted by American artist [[Charles Willson Peale]], 1805, who met Humboldt when he visited the U.S. in 1804]]

Humboldt saw the need for an approach to science that could account for the harmony of nature among the diversity of the physical world. For Humboldt, "the unity of nature" meant that it was the interrelation of all [[physical sciences]]—such as the conjoining between [[biology]], [[meteorology]] and [[geology]]—that determined where specific plants grew. He found these relationships by unraveling myriad, painstakingly collected data,{{sfn|Helferich|2004|p=25}} data extensive enough that it became an enduring foundation upon which others could base their work. Humboldt viewed nature [[holism|holistically]], and tried to explain natural phenomena without the appeal to religious dogma. He believed in the central importance of observation, and as a consequence had amassed a vast array of the most sophisticated scientific instruments then available. Each had its own velvet lined box and was the most accurate and portable of its time; nothing quantifiable escaped measurement. According to Humboldt, everything should be measured with the finest and most modern instruments and sophisticated techniques available, for that collected data was the basis of all scientific understanding.

This quantitative methodology would become known as [[Humboldtian science]]. Humboldt wrote "Nature herself is sublimely eloquent. The stars as they sparkle in firmament fill us with delight and ecstasy, and yet they all move in orbit marked out with mathematical precision."<ref>Alexander von Humboldt, ''Personal Narrative of Travels of the Equinocial Regions of the New Continent during Years 1799–1804'' (London, 1814), Vol. 1, pp.&nbsp;34–35</ref> However, [[Andreas Daum]] has recently revisited the concept of Humboldtian Science and set it apart from "Humboldt's science".{{sfn |Daum |2024b |pp=29–51 }}

[[File:Zentralbibliothek Zürich - Ideen zu einer Geographie der Pflanzen nebst einem Naturgemälde der Tropenländer - 000012142.jpg|thumb|Humboldt's ''Naturgemälde'', also known as the Chimborazo Map, is his depiction of the volcanoes Chimborazo and Cotopaxi in cross section, with detailed information about plant geography. The illustration was published in ''The Geography of Plants'', 1807, in a large format (54 cm x 84 cm). Largely used for global warming analyses, this map depicts in fact the vegetation of another volcano: the [[Antisana]].<ref>P. Moret ''et al.'', Humboldt's Tableau Physique revisited, PNAS, 2019 {{doi|10.1073/pnas.1904585116}}</ref>]]
His ''Essay on the Geography of Plants'' (published first in French and then German, both in 1807) was based on the then novel idea of studying the distribution of organic life as affected by varying physical conditions.<ref name="EB1911"/> This was most famously depicted in his published cross-section of Chimborazo, approximately two feet by three feet (54&nbsp;cm x 84&nbsp;cm) color pictorial, he called ''Ein Naturgemälde der Anden'' and what is also called the Chimborazo Map. It was a fold-out at the back of the publication.{{sfn|Zimmerer|2011|p=125}} Humboldt first sketched the map when he was in South America, which included written descriptions on either side of the cross-section of Chimborazo. These detailed the information on temperature, altitude, humidity, atmosphere pressure, and the animal and plants (with their scientific names) found at each elevation. Plants from the same genus appear at different elevations. The depiction is on an east-west axis going from the Pacific coast lowlands to the Andean range of which Chimborazo was a part, and the eastern Amazonian basin. Humboldt showed the three zones of coast, mountains, and Amazonia, based on his own observations, but he also drew on existing Spanish sources, particularly [[Pedro Cieza de León]], which he explicitly referred to. The Spanish American scientist [[Francisco José de Caldas]] had also measured and observed mountain environments and had earlier come to similar ideas about environmental factors in the distribution of life forms.{{sfn|Zimmerer|2011|p=129}} Humboldt was thus not putting forward something entirely new, but it is argued that his finding is not derivative either.<ref>Jorge Cañizares-Esguerra, ''How to Write the History of the New World: Histories, Epistemologies, and Identities in the Eighteenth-Century Atlantic World''. Stanford: Stanford University Press 2001.</ref> The Chimborazo map displayed complex information in an accessible fashion. The map was the basis for comparison with other major peaks. "The Naturgemälde showed for the first time that nature was a global force with corresponding climate zones across continents."<ref>{{harvnb|Wulf|2015|p=89}}. This publication includes Humboldt's first sketch of the ''Naturgemälde''.</ref> Another assessment of the map is that it "marked the beginning of a new era of environmental science, not only of mountain ecology but also of global-scale biogeophysical patterns and processes."{{sfn|Zimmerer|2011|p=125}}

[[File:Woodbridge_isothermal_chart3.jpg|thumb|Isothermal map of the world using Humboldt's data by [[William Channing Woodbridge]]]]

By his delineation (in 1817) of [[isothermal]] lines, he at once suggested the idea and devised the means of comparing the climatic conditions of various countries. He first investigated the rate of decrease in mean temperature with the increase in elevation above sea level, and afforded, by his inquiries regarding the origin of tropical storms, the earliest clue to the detection of the more complicated law governing atmospheric disturbances in higher latitudes.<ref name="EB1911"/><ref>Alexander von Humboldt, ''Des lignes isothermes et de la distribution de la châleur sur le globe''. Paris 1817.</ref> This was a major contribution to climatology.{{sfn|de Terra|1955|p=380}}<ref>A.H. Robinson and Helen M. Wallis. "Humboldt's Map of Isothermal Lines: a Milestone in Thematic Cartography". ''Cartographic Journal'' 4 (1967) 119–123.</ref>

His discovery of the decrease in intensity of Earth's [[magnetic field]] from the poles to the equator was communicated to the Paris Institute in a memoir read by him on 7 December 1804. Its importance was attested by the speedy emergence of rival claims.<ref name="EB1911"/>

His services to geology were based on his attentive study of the [[volcano]]es of the Andes and Mexico, which he observed and sketched, climbed, and measured with a variety of instruments. By climbing Chimborazo, he established an altitude record which became the basis for measurement of other volcanoes in the Andes and the Himalayas. As with other aspects of his investigations, he developed methods to show his synthesized results visually, using the graphic method of geologic-cross sections.{{sfn|de Terra|1955|pp=375–376}} He showed that volcanoes fell naturally into linear groups, presumably corresponding with vast subterranean fissures; and by his demonstration of the [[igneous rock|igneous]] origin of rocks previously held to be of aqueous formation, he contributed largely to the elimination of erroneous views, such as [[Neptunism]].<ref name="EB1911"/>

Humboldt was a significant contributor to cartography, creating maps, particularly of New Spain, that became the template for later mapmakers in Mexico. His careful recording of latitude and longitude led to accurate maps of Mexico, the port of Acapulco, the port of Veracruz, and the Valley of Mexico, and a map showing trade patterns among continents. His maps also included schematic information on geography, converting areas of administrative districts (intendancies) using proportional squares.<ref>Magali M. Carrera, ''Traveling from New Spain to Mexico: Mapping Practices of Nineteenth-century Mexico''. Durham: Duke University Press 2011, pp. 74–75.</ref> The U.S. was keen to see his maps and statistics on New Spain, since they had implication for territorial claims following the Louisiana Purchase.{{sfn|de Terra|1955|pp=177–178}} Later in life, Humboldt published three volumes (1836–39) examining sources that dealt with the early voyages to the Americas, pursuing his interest in nautical astronomy in the fifteenth and sixteenth centuries. His research yielded the origin of the name "America", put on a map of the Americas by [[Martin Waldseemüller]].<ref>Alexander von Humboldt, ''Examen critique de l'histoire de la géographie du Nouveau Continent et des progrès de l'astronomie nautique au 15e et 16e siècles''. Paris, 1836–39</ref>

[[File:Head-claw-Vultur-gryphus-Humboldt-Zoologie-T09p170.png|thumb|right|Humboldt's depiction of an [[Andean condor]], an example of his detailed drawing]]

Humboldt conducted a census of the indigenous and European inhabitants in [[New Spain]], publishing a schematized drawing of racial types and populations distribution, grouping them by region and social characteristics.<ref>Carrera, ''Mapping New Spain'', p. 76, reproducing the chart, illustration 23, p. 77.</ref> He estimated the population to be six million individuals.<ref>{{Cite book|last=Humboldt|first=Alexander von|title=Political Essay on the Kingdom of New Spain|year=1811|publisher=F. Schoell, Paris|language=fr}}</ref><ref>{{cite web|last=McCaa|first=Robert|title=The Peopling of Mexico from Origins to Revolution|publisher=Richard Steckel and Michael Haines (eds.). Cambridge University Press|date=8 December 1997|work=The Population History of North America|url=http://www.hist.umn.edu/~rmccaa/mxpoprev/cambridg3.htm|access-date=29 June 2015|archive-date=16 April 2016|archive-url=https://web.archive.org/web/20160416075826/http://www.hist.umn.edu/~rmccaa/mxpoprev/cambridg3.htm|url-status=live}}</ref> He estimated Indians to be forty percent of New Spain's population, but their distribution being uneven; the most dense were in the center and south of Mexico, the least dense in the north. He presented these data in chart form, for easier understanding.<ref>Humboldt, ''Political essay on the Kingdom of New Spain'', chapter entitled "Indians".</ref> He also surveyed the non-Indian population, categorized as Whites (Spaniards), ''Negroes'', and castes (''[[casta]]s'').<ref>Humboldt, ''Political essay'', chapter entitled "Whites, Negroes, Castes".</ref> American-born Spaniards, so-called ''[[Criollo people|creoles]]'' had been [[pintura de castas|painting depictions of mixed-race family groupings]] in the eighteenth century, showing father of one racial category, mother of another, and the offspring in a third category in hierarchical order, so racial hierarchy was an essential way elites viewed Mexican society.<ref>Ilona Katzew, ''Casta Painting''. New Haven: Yale University Press.</ref> Humboldt reported that American-born Spaniards were legally racial equals of [[peninsulares|those born in Spain]], but the crown policy since the Bourbons took the Spanish throne privileged those born in Iberia. Humboldt observed that "the most miserable European, without education and without intellectual cultivation, thinks himself superior to whites born in the new continent".<ref>Humboldt, ''Political essay'', p. 71.</ref> The truth in this assertion, and the conclusions derived from them, have been often disputed as superficial, or politically motivated, by some authors, considering that between 40% and 60% of high offices in the new world were held by creoles.<ref>P. Victoria "Grandes mitos de la historia de Colombia" (Great myths in Colombian History). Grupo Planeta – Colombia, May 31, 2011</ref><ref name="José Oscar Frigerio 1801">José Oscar Frigerio, La rebelión criolla de Oruro fue juzgada en Buenos Aires (1781–1801), Ediciones del Boulevard, Córdoba, 2011.</ref>
The enmity between some creoles and the peninsular-born whites increasingly became an issue in the late period of Spanish rule, with creoles increasingly alienated from the crown. Humboldt's assessment was that royal government abuses and the example of [[American Revolution|a new model of rule]] in the United States were eroding the unity of whites in New Spain.<ref>Humboldt, ''Political essay'', p. 72.</ref> Humboldt's writings on race in New Spain were shaped by the memorials of the [[classical liberal]], enlightened Bishop-elect of Michoacán, [[Manuel Abad y Queipo]], who personally presented Humboldt with his printed memorials to the Spanish crown critiquing social and economic conditions and his recommendations for eliminating them.<ref>D.A. Brading, ''Church and State in Bourbon Mexico: The Diocese of Michoacán 1749–1810''. Cambridge: Cambridge University Press 1994, p. 228.</ref><ref name="José Oscar Frigerio 1801"/>

One scholar says that his writings contain fantastical descriptions of America, while leaving out its inhabitants, stating that Humboldt, coming from the [[Romanticism|Romantic]] school of thought, believed '...&nbsp;nature is perfect till man deforms it with care'.<ref name="Pratt 1997">{{Cite book|last=Pratt|first=Mary Louise|author-link=Mary Louise Pratt|title=Imperial Eyes: Travel Writing and Transculturation|year=1997|publisher=Routledge|location=London|isbn=0415060958}}</ref> The further assessment is that he largely neglected the human societies amidst nature. Views of indigenous peoples as 'savage' or 'unimportant' leaves them out of the historical picture.<ref name="Pratt 1997"/> Other scholars counter that Humboldt dedicated large parts of his work to describing the [[Slavery in the Spanish Empire|conditions of slaves]], indigenous peoples, mixed-race [[castas]], and society in general. He often showed his disgust for the slavery<ref>{{cite book|last=McCullough|first=David|author-link=David McCullough|title=Brave Companions. Portraits of History|publisher=Simon & Schuster|date=1992|page=[https://archive.org/details/bravecompanions00davi/page/3 3ff]|isbn=0-6717-9276-8|url=https://archive.org/details/bravecompanions00davi/page/3}}</ref> and inhumane conditions in which indigenous peoples and others were treated and he often criticized Spanish colonial policies.{{sfn|Rupke|2008|p=138}}

Humboldt was not primarily an artist, but he could draw well, allowing him to record a visual record of particular places and their natural environment. Many of his drawings became the basis for illustrations of his many scientific and general publications. Artists whom Humboldt influenced, such as [[Johann Moritz Rugendas]], followed in his path and painted the same places Humboldt had visited and recorded, such as the basalt formations in Mexico, which was an illustration in his ''Vues des Cordillères''.<ref>Alexander von Humboldt, ''Vues des Cordillères et monumens des peuples indigènes de l'Amerique''. Paris: F. Schoell, 180–13.</ref><ref>Sigrid Achenbach, ''Kunst um Humboldt: Reisestudien aus Mittel- un Südamerika von Rugendas, Bellermann un Hildebrandt im Berliner Kupferstichkabinett''. Munich: Hirmer Verlag München 2009, 105, catalog 52.</ref>

The editing and publication of the encyclopedic mass of scientific, political and archaeological material that had been collected by him during his absence from Europe was now Humboldt's most urgent desire. After a short trip to Italy with [[Joseph Louis Gay-Lussac]] for the purpose of investigating the law of [[magnetic declination]] and a stay of two and a half years in Berlin, in the spring of 1808, he settled in Paris. His purpose for being located there was to secure the scientific cooperation required for bringing his great work through the press. This colossal task, which he at first hoped would occupy but two years, eventually cost him twenty-one, and even then it remained incomplete.

{{Gallery
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|File:HumboldtHouseDF.JPG
|House where Humboldt and Bonpland lived in [[Mexico City]] in 1803, located at 80 Rep. de Uruguay in the [[Centro (Mexico City)|historic centre]], just south of the [[Zocalo]]

|File:StatueAlexHumboldtMexico.JPG
|Statue to Humboldt in Alameda Park, Mexico City, erected 1999 on the two hundredth-anniversary of the beginning of his travels to Spanish America

|File:Humboldt_-_Cuernavaca_I.jpg
|Statue of Humboldt in [[Cuernavaca]], [[Mexico]]

|File:Prismas Basálticos, Huasca de Ocampo, Hidalgo, México, 2013-10-10, DD 42.JPG
|Waterfall over the [[Basaltic Prisms of Santa María Regla]], [[Huasca de Ocampo]], Hidalgo, Mexico, that Humboldt sketched
}}